NIST SP 800-53 Learning Center
Study this control family as a connected set of risk outcomes, implementation decisions, evidence expectations, and assessment questions.
Control family
Use the family as a planning boundary, but assess each selected control against the system context, inherited services, organization-defined parameters, and evidence available from real operations.
Family catalog
Base controls open full profiles. Enhancement results link directly to the corresponding enhancement section on the parent control page.
System and information integrity policy and procedures address the controls in the SI family that are implemented within systems and organizations. The risk management strategy is an important factor in establishing such policies and procedures. Policies and procedures contribute to security and privacy assurance. Therefore, it is important that security and
The need to remediate system flaws applies to all types of software and firmware. Organizations identify systems affected by software flaws, including potential vulnerabilities resulting from those flaws, and report this information to designated organizational personnel with information security and privacy responsibilities. Organizations consider establish
System entry and exit points include firewalls, remote access servers, workstations, electronic mail servers, web servers, proxy servers, notebook computers, and mobile devices. Malicious code includes viruses, worms, Trojan horses, and spyware. Malicious code can also be encoded in various formats contained within compressed or hidden files or hidden in fil
System monitoring includes external and internal monitoring. External monitoring includes the observation of events occurring at external interfaces to the system. Internal monitoring includes the observation of events occurring within the system. Organizations monitor systems by observing audit activities in real time or by observing other system aspects su
The Cybersecurity and Infrastructure Security Agency (CISA) generates security alerts and advisories to maintain situational awareness throughout the Federal Government. Security directives are issued by OMB or other designated organizations with the responsibility and authority to issue such directives. Compliance with security directives is essential due t
Transitional states for systems include system startup, restart, shutdown, and abort. System notifications include hardware indicator lights, electronic alerts to system administrators, and messages to local computer consoles. In contrast to security function verification, privacy function verification ensures that privacy functions operate as expected and a
Unauthorized changes to software, firmware, and information can occur due to errors or malicious activity. Software includes operating systems (with key internal components, such as kernels or drivers), middleware, and applications. Firmware interfaces include Unified Extensible Firmware Interface (UEFI) and Basic Input/Output System (BIOS). Information incl
System entry and exit points include firewalls, remote-access servers, electronic mail servers, web servers, proxy servers, workstations, notebook computers, and mobile devices. Spam can be transported by different means, including email, email attachments, and web accesses. Spam protection mechanisms include signature definitions.
NIST SP 800-53 SI-9 Information Input Restrictions.
Checking the valid syntax and semantics of system inputs—including character set, length, numerical range, and acceptable values—verifies that inputs match specified definitions for format and content. For example, if the organization specifies that numerical values between 1-100 are the only acceptable inputs for a field in a given application, inputs of "3
Organizations consider the structure and content of error messages. The extent to which systems can handle error conditions is guided and informed by organizational policy and operational requirements. Exploitable information includes stack traces and implementation details; erroneous logon attempts with passwords mistakenly entered as the username; mission
Information management and retention requirements cover the full life cycle of information, in some cases extending beyond system disposal. Information to be retained may also include policies, procedures, plans, reports, data output from control implementation, and other types of administrative information. The National Archives and Records Administration (
While MTTF is primarily a reliability issue, predictable failure prevention is intended to address potential failures of system components that provide security capabilities. Failure rates reflect installation-specific consideration rather than the industry-average. Organizations define the criteria for the substitution of system components based on the MTTF
Implementation of non-persistent components and services mitigates risk from advanced persistent threats (APTs) by reducing the targeting capability of adversaries (i.e., window of opportunity and available attack surface) to initiate and complete attacks. By implementing the concept of non-persistence for selected system components, organizations can provid
Certain types of attacks, including SQL injections, produce output results that are unexpected or inconsistent with the output results that would be expected from software programs or applications. Information output filtering focuses on detecting extraneous content, preventing such extraneous content from being displayed, and then alerting monitoring tools
Some adversaries launch attacks with the intent of executing code in non-executable regions of memory or in memory locations that are prohibited. Controls employed to protect memory include data execution prevention and address space layout randomization. Data execution prevention controls can either be hardware-enforced or software-enforced with hardware en
Failure conditions include the loss of communications among critical system components or between system components and operational facilities. Fail-safe procedures include alerting operator personnel and providing specific instructions on subsequent steps to take. Subsequent steps may include doing nothing, reestablishing system settings, shutting down proc
Personally identifiable information quality operations include the steps that organizations take to confirm the accuracy and relevance of personally identifiable information throughout the information life cycle. The information life cycle includes the creation, collection, use, processing, storage, maintenance, dissemination, disclosure, and disposal of per
De-identification is the general term for the process of removing the association between a set of identifying data and the data subject. Many datasets contain information about individuals that can be used to distinguish or trace an individual’s identity, such as name, social security number, date and place of birth, mother’s maiden name, or biometric recor
Many cyber-attacks target organizational information, or information that the organization holds on behalf of other entities (e.g., personally identifiable information), and exfiltrate that data. In addition, insider attacks and erroneous user procedures can remove information from the system that is in violation of the organizational policies. Tainting appr
NIST SP 800-53 enhancement SI-2(1) Central Management.
Retaining information for longer than it is needed makes it an increasingly valuable and enticing target for adversaries. Keeping information available for the minimum period of time needed to support organizational missions or business functions reduces the opportunity for adversaries to compromise, capture, and exfiltrate that information.
Automated mechanisms can track and determine the status of known flaws for system components.
Actions taken by a system service or a function are often driven by the information it receives. Corruption, fabrication, modification, or deletion of that information could impact the ability of the service function to properly carry out its intended actions. By having multiple sources of input, the service or function can continue operation if one source i
Organizations determine the time it takes on average to correct system flaws after such flaws have been identified and subsequently establish organizational benchmarks (i.e., time frames) for taking corrective actions. Benchmarks can be established by the type of flaw or the severity of the potential vulnerability if the flaw can be exploited.
One objective of the advanced persistent threat is to exfiltrate valuable information. Once exfiltrated, there is generally no way for the organization to recover the lost information. Therefore, organizations may consider dividing the information into disparate elements and distributing those elements across multiple systems or system components and locatio
Using automated tools to support patch management helps to ensure the timeliness and completeness of system patching operations.
Due to system integrity and availability concerns, organizations consider the methodology used to carry out automatic updates. Organizations balance the need to ensure that the updates are installed as soon as possible with the need to maintain configuration management and control with any mission or operational impacts that automatic updates might impose (i
Previous versions of software or firmware components that are not removed from the system after updates have been installed may be exploited by adversaries. Some products may automatically remove previous versions of software and firmware from the system.
Root cause analysis includes a wide range of approaches, tools, and techniques to systematically identify the underlying cause of issues or failures to systems and systems components (hardware, software, and firmware). Organizations consider the severity of the incident to determine what root cause analysis method is used and how quickly implementation of th
NIST SP 800-53 enhancement SI-3(1) Central Management.
NIST SP 800-53 enhancement SI-3(2) Automatic Updates.
NIST SP 800-53 enhancement SI-3(3) Non-privileged Users.
Protection mechanisms for malicious code are typically categorized as security-related software and, as such, are only updated by organizational personnel with appropriate access privileges.
NIST SP 800-53 enhancement SI-3(5) Portable Storage Devices.
None.
NIST SP 800-53 enhancement SI-3(7) Nonsignature-based Detection.
Detecting unauthorized commands can be applied to critical interfaces other than kernel-based interfaces, including interfaces with virtual machines and privileged applications. Unauthorized operating system commands include commands for kernel functions from system processes that are not trusted to initiate such commands as well as commands for kernel funct
NIST SP 800-53 enhancement SI-3(9) Authenticate Remote Commands.
Linking individual intrusion detection tools into a system-wide intrusion detection system provides additional coverage and effective detection capabilities. The information contained in one intrusion detection tool can be shared widely across the organization, making the system-wide detection capability more robust and powerful.
Automated tools and mechanisms include host-based, network-based, transport-based, or storage-based event monitoring tools and mechanisms or security information and event management (SIEM) technologies that provide real-time analysis of alerts and notifications generated by organizational systems. Automated monitoring techniques can create unintended privac
Using automated tools and mechanisms to integrate intrusion detection tools and mechanisms into access and flow control mechanisms facilitates a rapid response to attacks by enabling the reconfiguration of mechanisms in support of attack isolation and elimination.
Unusual or unauthorized activities or conditions related to system inbound and outbound communications traffic includes internal traffic that indicates the presence of malicious code or unauthorized use of legitimate code or credentials within organizational systems or propagating among system components, signaling to external systems, and the unauthorized e
Alerts may be generated from a variety of sources, including audit records or inputs from malicious code protection mechanisms, intrusion detection or prevention mechanisms, or boundary protection devices such as firewalls, gateways, and routers. Alerts can be automated and may be transmitted telephonically, by electronic mail messages, or by text messaging.
NIST SP 800-53 enhancement SI-4(6) Restrict Non-privileged Users.
Least-disruptive actions include initiating requests for human responses.
NIST SP 800-53 enhancement SI-4(8) Protection of Monitoring Information.
Testing intrusion-monitoring tools and mechanisms is necessary to ensure that the tools and mechanisms are operating correctly and continue to satisfy the monitoring objectives of organizations. The frequency and depth of testing depends on the types of tools and mechanisms used by organizations and the methods of deployment.
The significant number of changes to organizational systems and environments of operation requires the dissemination of security-related information to a variety of organizational entities that have a direct interest in the success of organizational mission and business functions. Based on information provided by security alerts and advisories, changes may b
NIST SP 800-53 enhancement SI-6(1) Notification of Failed Security Tests.
The use of automated mechanisms to support the management of distributed function testing helps to ensure the integrity, timeliness, completeness, and efficacy of such testing.
Organizational personnel with potential interest in the results of the verification of security and privacy functions include systems security officers, senior agency information security officers, and senior agency officials for privacy.
Security-relevant events include the identification of new threats to which organizational systems are susceptible and the installation of new hardware, software, or firmware. Transitional states include system startup, restart, shutdown, and abort.
The employment of automated tools to report system and information integrity violations and to notify organizational personnel in a timely matter is essential to effective risk response. Personnel with an interest in system and information integrity violations include mission and business owners, system owners, senior agency information security official, se
Centrally managed integrity verification tools provides greater consistency in the application of such tools and can facilitate more comprehensive coverage of integrity verification actions.
NIST SP 800-53 enhancement SI-7(4) Tamper-evident Packaging.
Organizations may define different integrity-checking responses by type of information, specific information, or a combination of both. Types of information include firmware, software, and user data. Specific information includes boot firmware for certain types of machines. The automatic implementation of controls within organizational systems includes rever
Cryptographic mechanisms used to protect integrity include digital signatures and the computation and application of signed hashes using asymmetric cryptography, protecting the confidentiality of the key used to generate the hash, and using the public key to verify the hash information. Organizations that employ cryptographic mechanisms also consider cryptog
Integrating detection and response helps to ensure that detected events are tracked, monitored, corrected, and available for historical purposes. Maintaining historical records is important for being able to identify and discern adversary actions over an extended time period and for possible legal actions. Security-relevant changes include unauthorized chang
Organizations select response actions based on types of software, specific software, or information for which there are potential integrity violations.
Ensuring the integrity of boot processes is critical to starting system components in known, trustworthy states. Integrity verification mechanisms provide a level of assurance that only trusted code is executed during boot processes.
NIST SP 800-53 enhancement SI-8(1) Central Management.
Using automated mechanisms to update spam protection mechanisms helps to ensure that updates occur on a regular basis and provide the latest content and protection capabilities.
Learning mechanisms include Bayesian filters that respond to user inputs that identify specific traffic as spam or legitimate by updating algorithm parameters and thereby more accurately separating types of traffic.
In certain situations, such as during events that are defined in contingency plans, a manual override capability for input validation may be needed. Manual overrides are used only in limited circumstances and with the inputs defined by the organization.
Resolution of input validation errors includes correcting systemic causes of errors and resubmitting transactions with corrected input. Input validation errors are those related to the information inputs defined by the organization in the base control ( [SI-10](#si-10)).
A common vulnerability in organizational systems is unpredictable behavior when invalid inputs are received. Verification of system predictability helps ensure that the system behaves as expected when invalid inputs are received. This occurs by specifying system responses that allow the system to transition to known states without adverse, unintended side ef
In addressing invalid system inputs received across protocol interfaces, timing interactions become relevant, where one protocol needs to consider the impact of the error response on other protocols in the protocol stack. For example, 802.11 standard wireless network protocols do not interact well with Transmission Control Protocols (TCP) when packets are dr
Restricting the use of inputs to trusted sources and in trusted formats applies the concept of authorized or permitted software to information inputs. Specifying known trusted sources for information inputs and acceptable formats for such inputs can reduce the probability of malicious activity. The information inputs are those defined by the organization in
Untrusted data injections may be prevented using a parameterized interface or output escaping (output encoding). Parameterized interfaces separate data from code so that injections of malicious or unintended data cannot change the semantics of commands being sent. Output escaping uses specified characters to inform the interpreter’s parser whether data is tr
Limiting the use of personally identifiable information throughout the information life cycle when the information is not needed for operational purposes helps to reduce the level of privacy risk created by a system. The information life cycle includes information creation, collection, use, processing, storage, maintenance, dissemination, disclosure, and dis
Organizations can minimize the risk to an individual’s privacy by employing techniques such as de-identification or synthetic data. Limiting the use of personally identifiable information throughout the information life cycle when the information is not needed for research, testing, or training helps reduce the level of privacy risk created by a system. Risk
Organizations can minimize both security and privacy risks by disposing of information when it is no longer needed. The disposal or destruction of information applies to originals as well as copies and archived records, including system logs that may contain personally identifiable information.
Transferring primary system component responsibilities to other substitute components prior to primary component failure is important to reduce the risk of degraded or debilitated mission or business functions. Making such transfers based on a percentage of mean time to failure allows organizations to be proactive based on their risk tolerance. However, the
NIST SP 800-53 enhancement SI-13(2) Time Limit on Process Execution Without Supervision.
For example, if the MTTF for a system component is 100 days and the MTTF percentage defined by the organization is 90 percent, the manual transfer would occur after 90 days.
Automatic or manual transfer of components from standby to active mode can occur upon the detection of component failures.
Failover refers to the automatic switchover to an alternate system upon the failure of the primary system. Failover capability includes incorporating mirrored system operations at alternate processing sites or periodic data mirroring at regular intervals defined by the recovery time periods of organizations.
Trusted sources include software and data from write-once, read-only media or from selected offline secure storage facilities.
Retaining information longer than is needed makes the information a potential target for advanced adversaries searching for high value assets to compromise through unauthorized disclosure, unauthorized modification, or exfiltration. For system-related information, unnecessary retention provides advanced adversaries information that can assist in their reconn
Persistent connections to systems can provide advanced adversaries with paths to move laterally through systems and potentially position themselves closer to high value assets. Limiting the availability of such connections impedes the adversary’s ability to move freely through organizational systems.
The use of automated mechanisms to improve data quality may inadvertently create privacy risks. Automated tools may connect to external or otherwise unrelated systems, and the matching of records between these systems may create linkages with unintended consequences. Organizations assess and document these risks in their privacy impact assessments and make d
Data tagging personally identifiable information includes tags that note processing permissions, authority to process, de-identification, impact level, information life cycle stage, and retention or last updated dates. Employing data tags for personally identifiable information can support the use of automation tools to correct or delete relevant personally
Individuals or their designated representatives can be sources of correct personally identifiable information. Organizations consider contextual factors that may incentivize individuals to provide correct data versus false data. Additional steps may be necessary to validate collected information based on the nature and context of the personally identifiable
Inaccurate personally identifiable information maintained by organizations may cause problems for individuals, especially in those business functions where inaccurate information may result in inappropriate decisions or the denial of benefits and services to individuals. Even correct information, in certain circumstances, can cause problems for individuals t
When personally identifiable information is corrected or deleted, organizations take steps to ensure that all authorized recipients of such information, and the individual with whom the information is associated or their designated representatives, are informed of the corrected or deleted information.
If a data source contains personally identifiable information but the information will not be used, the dataset can be de-identified when it is created by not collecting the data elements that contain the personally identifiable information. For example, if an organization does not intend to use the social security number of an applicant, then application fo
Datasets can be archived for many reasons. The envisioned purposes for the archived dataset are specified, and if personally identifiable information elements are not required, the elements are not archived. For example, social security numbers may have been collected for record linkage, but the archived dataset may include the required elements from the lin
Prior to releasing a dataset, a data custodian considers the intended uses of the dataset and determines if it is necessary to release personally identifiable information. If the personally identifiable information is not necessary, the information can be removed using de-identification techniques.
There are many possible processes for removing direct identifiers from a dataset. Columns in a dataset that contain a direct identifier can be removed. In masking, the direct identifier is transformed into a repeating character, such as XXXXXX or 999999. Identifiers can be encrypted or hashed so that the linked records remain linked. In the case of encryptio
Many types of statistical analyses can result in the disclosure of information about individuals even if only summary information is provided. For example, if a school that publishes a monthly table with the number of minority students enrolled, reports that it has 10-19 such students in January, and subsequently reports that it has 20-29 such students in Ma
The mathematical definition for differential privacy holds that the result of a dataset analysis should be approximately the same before and after the addition or removal of a single data record (which is assumed to be the data from a single individual). In its most basic form, differential privacy applies only to online query systems. However, it can also b
Algorithms that appear to remove personally identifiable information from a dataset may in fact leave information that is personally identifiable or data that is re-identifiable. Software that is claimed to implement a validated algorithm may contain bugs or implement a different algorithm. Software may de-identify one type of data, such as integers, but not
A motivated intruder test is a test in which an individual or group takes a data release and specified resources and attempts to re-identify one or more individuals in the de-identified dataset. Such tests specify the amount of inside knowledge, computational resources, financial resources, data, and skills that intruders possess to conduct the tests. A moti
The use of malicious code analysis tools provides organizations with a more in-depth understanding of adversary tradecraft (i.e., tactics, techniques, and procedures) and the functionality and purpose of specific instances of malicious code. Understanding the characteristics of malicious code facilitates effective organizational responses to current and futu
Organizations balance the need to encrypt communications traffic to protect data confidentiality with the need to maintain visibility into such traffic from a monitoring perspective. Organizations determine whether the visibility requirement applies to internal encrypted traffic, encrypted traffic intended for external destinations, or a subset of the traffi
Organization-defined interior points include subnetworks and subsystems. Anomalies within organizational systems include large file transfers, long-time persistent connections, attempts to access information from unexpected locations, the use of unusual protocols and ports, the use of unmonitored network protocols (e.g., IPv6 usage during IPv4 transition), a
Organizational personnel on the system alert notification list include system administrators, mission or business owners, system owners, senior agency information security officer, senior agency official for privacy, system security officers, or privacy officers. Automated organization-generated alerts are the security alerts generated by organizations and t
Identifying and understanding common communications traffic and event patterns help organizations provide useful information to system monitoring devices to more effectively identify suspicious or anomalous traffic and events when they occur. Such information can help reduce the number of false positives and false negatives during system monitoring.
Wireless signals may radiate beyond organizational facilities. Organizations proactively search for unauthorized wireless connections, including the conduct of thorough scans for unauthorized wireless access points. Wireless scans are not limited to those areas within facilities containing systems but also include areas outside of facilities to verify that u
Wireless networks are inherently less secure than wired networks. For example, wireless networks are more susceptible to eavesdroppers or traffic analysis than wireline networks. When wireless to wireline communications exist, the wireless network could become a port of entry into the wired network. Given the greater facility of unauthorized network access v
Correlating information from different system monitoring tools and mechanisms can provide a more comprehensive view of system activity. Correlating system monitoring tools and mechanisms that typically work in isolation—including malicious code protection software, host monitoring, and network monitoring—can provide an organization-wide monitoring view and m
Correlating monitoring information from a more diverse set of information sources helps to achieve integrated situational awareness. Integrated situational awareness from a combination of physical, cyber, and supply chain monitoring activities enhances the capability of organizations to more quickly detect sophisticated attacks and investigate the methods an
Organization-defined interior points include subnetworks and subsystems. Covert means that can be used to exfiltrate information include steganography.
Indications of increased risk from individuals can be obtained from different sources, including personnel records, intelligence agencies, law enforcement organizations, and other sources. The monitoring of individuals is coordinated with the management, legal, security, privacy, and human resource officials who conduct such monitoring. Monitoring is conduct
Privileged users have access to more sensitive information, including security-related information, than the general user population. Access to such information means that privileged users can potentially do greater damage to systems and organizations than non-privileged users. Therefore, implementing additional monitoring on privileged users helps to ensure
During probationary periods, employees do not have permanent employment status within organizations. Without such status or access to information that is resident on the system, additional monitoring can help identify any potentially malicious activity or inappropriate behavior.
Unauthorized or unapproved network services include services in service-oriented architectures that lack organizational verification or validation and may therefore be unreliable or serve as malicious rogues for valid services.
Host-based monitoring collects information about the host (or system in which it resides). System components in which host-based monitoring can be implemented include servers, notebook computers, and mobile devices. Organizations may consider employing host-based monitoring mechanisms from multiple product developers or vendors.
Indicators of compromise (IOC) are forensic artifacts from intrusions that are identified on organizational systems at the host or network level. IOCs provide valuable information on systems that have been compromised. IOCs can include the creation of registry key values. IOCs for network traffic include Universal Resource Locator or protocol elements that i
Encrypted traffic, asymmetric routing architectures, capacity and latency limitations, and transitioning from older to newer technologies (e.g., IPv4 to IPv6 network protocol transition) may result in blind spots for organizations when analyzing network traffic. Collecting, decrypting, pre-processing, and distributing only relevant traffic to monitoring devi
Unauthorized modifications to boot firmware may indicate a sophisticated, targeted attack. These types of targeted attacks can result in a permanent denial of service or a persistent malicious code presence. These situations can occur if the firmware is corrupted or if the malicious code is embedded within the firmware. System components can protect the inte
NIST SP 800-53 enhancement SI-7(11) Confined Environments with Limited Privileges.
Organizations verify the integrity of user-installed software prior to execution to reduce the likelihood of executing malicious code or programs that contains errors from unauthorized modifications. Organizations consider the source of the software, ensuring the software and updates come from authorized sources and/or sites, and the practicality of approach
NIST SP 800-53 enhancement SI-7(13) Code Execution in Protected Environments.
NIST SP 800-53 enhancement SI-7(14) Binary or Machine Executable Code.
Cryptographic authentication includes verifying that software or firmware components have been digitally signed using certificates recognized and approved by organizations. Code signing is an effective method to protect against malicious code. Organizations that employ cryptographic mechanisms also consider cryptographic key management solutions.
Placing a time limit on process execution without supervision is intended to apply to processes for which typical or normal execution periods can be determined and situations in which organizations exceed such periods. Supervision includes timers on operating systems, automated responses, and manual oversight and response when system process anomalies occur.
Runtime application self-protection employs runtime instrumentation to detect and block the exploitation of software vulnerabilities by taking advantage of information from the software in execution. Runtime exploit prevention differs from traditional perimeter-based protections such as guards and firewalls which can only detect and block attacks by using ne
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Planned Academy connection
These titles come from the approved NIST SP 800-53 course plan. They are shown as planned coverage and do not claim a public lesson URL before publication.
